Cellular mechanisms for the uptake, transport, digestion, excretion and storage of proteins, lipids, carbohydrates and metals in normal tissues, experimental models of disease and in human disorders will be studied utilizing cytochemical procedures for demonstrating tracer compounds in the light and electron microscope. Enzymatic staining procedures for demonstrating the endoplasmic reticulum, mitochondria, Golgi apparatus, lysosomes, peroxisomes and nucleic acids will be employed. Although emphasis will be placed on hepatocytes, neurons, renal parenchymal cells and endocrine organs other cells will be studied in the investigation of generalized metabolic disorders. Morphological studies will be coordinated with biochemical analyses of subcellular fractions, secretions and whole tissues. The development of new staining procedures for ultrastructural study will be pursued.